I found this site while searching for an answer to the following need.

I am adding an 18 HP Sabb to my 31 foot power trimaran - I have aton of headroom over the engine and want to use a stand pipe muffler - just like the one in George Buehler's "Buehler's Backyard Boatbuilding" as shown on page 189.

I am not finding these types of standpipes in the catalogs - I really want one in Plastic or FRP, no way would I tolerate Stainless Steel - am I going to have to construct one from Vernatube?

Thanks for the link Phil. I don't know the principals and construction details of water mufflers, and I am not one to install items I don't understand on my boat.

The Sabb manuals, and the Buehler sketch both show a standpipe. Sabb even shows a system that is just a hose that sweeps up then back down with no devices installed along its length at all.

I like systems to be as simple as possible, but I wanted to know if there was some issue with standpipes that lead to them being replaced by waterlifts. Now I think the reason is head space for a standpipe, which is not an issue in my boat.

I really don't like the issue with waterlifts of them filling with water when you turn the engine over without it firing and then they fill up.

Thanks for the link Phil. I don't know the principals and construction details of water mufflers, and I am not one to install items I don't understand on my boat.

The Sabb manuals, and the Buehler sketch both show a standpipe. Sabb even shows a system that is just a hose that sweeps up then back down with no devices installed along its length at all.

I like systems to be as simple as possible, but I wanted to know if there was some issue with standpipes that lead to them being replaced by waterlifts. Now I think the reason is head space for a standpipe, which is not an issue in my boat.

I really don't like the issue with waterlifts of them filling with water when you turn the engine over without it firing and then they fill up.

Non-water cooled exhausts are extremely dangerous for a variety of reasons.

However if the run internally is short and lagged properly..they have been safe and successful since the beginning of internal combustion engines.

Buehler suggests many things that are borderline issues with insuring a boat....many surveyors (right or wrong) will make note of things that insurance companies will follow blindly...and I feel Buehler's back yard boat concept is to have inexpensive boats that he might not even consider insuring ( I did have his book for decades).

Sorry...didn't associate standpipe with water cooling...been awhile since looking at home-built or other old timer stuff.

The exhaust Phil linked looks like it would be easy enough to home construct.

Almost as easy is a simple water pipe U shaped riser to the height desired (lagged) an the water injected after the riser , before any hose hook up.

Although with out the discount Vetus prices are insane , they have mfg. stand pipe units that might fit your requirements.

Lift mufflers are great , if of large enough size , and with a remote drain (required anyway to winterize) offer little danger.

The QUIET underway is impressive!

On our 90/90 we used a 12 inch GRP lift muffler to feed a Vetus stand oipe and overboard discharge amidships.
The only exhaust noise is the cooling water dropping from the exhaust fitting to the water.

The boat can be rolled 90Deg with no water coming up the exhaust , so no need to close a sea cock for ocean use.

Why not stainless? Your dry stack temps will get pretty hot, far more than a non-metallic can tolerate. Saab diesel - when was the last time it was running properly under a 70%+ load? Can you still get parts?

Many sailboats had atomic4s a 25hp gas engine, the eshuast was often galvanized pipe. A threaded flange at the end of the manifold followed by a street ell than the riser pipe topped with two elbows to direct the flow down again. Then a short piece of pipe with a hose barb tapped in it injected the water into the exhaust. From there it was all hose.

From the end of the exhaust manifold to the water injection area was all wrapped in asbestos tape.

My 1975 Catalina 27 came that way from the factory and I had no problem with insuring it. Replacement parts where at any hardware store.